1. Technical Field
The present invention relates to a switching apparatus and a test apparatus. In particular, the present invention relates to a switching apparatus, and a test apparatus, connecting a transmission line designated from among a plurality of transmission lines provided between an input terminal and an output terminal.
2. Related Art
A switching apparatus including a plurality of transmission lines provided between an input terminal and an output terminal, and transmitting a signal by selecting one transmission line designated from among the plurality of transmission lines by means of a control signal is known. Such a known switching apparatus connects the selected transmission line between the input terminal and the output terminal. For example, the plurality of transmission lines may be a plurality of transmission lines having different attenuation quantity of signals from each other. According to this, the switching apparatus is able to select between outputting an input signal after attenuation, and/or selecting the attenuation quantity by which the input signal is to be attenuated. For example in a test apparatus for testing the characteristics of a device under test, such a switching apparatus is usable for outputting a test signal to be supplied to a device under test after switching between attenuating the test signal to a predetermined amplitude and not attenuating the test signal, and the like.
In connecting one transmission line selected from among a plurality of transmission lines, between the input terminal and the output terminal, the switching apparatus cuts off the other transmission lines, from the input terminal and the output terminal. When pursuing this, there are cases where, for example in the switching apparatus, a signal applied to the switch having been cut off is propagated along a control wiring as a noise by being conveyed to the control wiring by means of the capacitance coupling or the like. Moreover, such a noise may reach the switch at the output side by being propagated on the control wiring, and be superposed on an output signal by means of the capacitive coupling again. In such a case, it becomes difficult to transmit the test signal with accuracy, and further to test a device under test with accuracy or to measure the characteristics of a device under test with accuracy.